Install letter_opener
Update readme
Refactor processes recording spec
Add comments to admin mailers
Convert emails to markdown
Only show appropriate state buttons
Change email prose
Move email input to a partial
Merge branch 'feature-email-comments'

* feature-email-comments:
  Move email input to a partial
  Change email prose
  Only show appropriate state buttons
  Convert emails to markdown
  Add comments to admin mailers
  Refactor processes recording spec
  Update readme